1. Field of the Invention
This invention relates to a device for attachment of multiple structural support brackets to the vertical frame components at the front side of a switch box, in which equipment holders provided with threaded connectors can be attached to the frame components and the front plates of the support brackets can be screwed to the threaded connectors.
2. Description of the Prior Art
In known devices of this type, equipment holders are formed as angular pieces which have, in one piece, a threaded connector for screwing to the front plate of the support bracket, and have, in the other piece, a bore for an attachment screw, by means of which the angular piece is attached to the frame component. The frame component has an opening T-slot into which strips having threaded bores positioned at intervals may be inserted.
These prior art devices have the advantage that, between the angular pieces, sufficient space exists to connect the support brackets to the switch box by means of a telescoping extension, so that, after loosening the attaching screws which connect the front plate to the angular pieces, it can be removed from the switch box. Since the strip pieces having threaded bores determine the positioning locations, the vertical intervals of the support brackets cannot be varied in the switch box, and are therefore firmly specified.
A device is also known in which specially formed nuts can be inserted into the open T-slot formed in the frame component. These special nuts can be inserted vertically into the T-slot, and may be retained in the T-slot by means of a spring, to facilitate screwing in of an attaching screw.
With this known device, the vertical interval of the support brackets on the switch box can be continuously varied. Between the attachment points to the frame pieces, however, there is no space to pass out a telescoping extension. The support brackets thus cannot be attached on the switch box by means of a telescoping extension.